You can use any third-party edit control available as jQuery plugin in data input forms. Typically all you need is to
write a small function in JavaScript that initializes the editor and call this function from
OnInsertFormLoaded
and
OnEditFormLoaded
event handlers.

The page below allows you to edit the contents of the function_code field using the
CodeMirror editor that provides syntax highlighting, code folding,
autocompletion, and other useful features. Open Insert or Edit
forms to see the editor in action.